Feeding mechanism for sewing machines



Aug. 4,1942 F. F. ZEIER 2,292,258

FEEDING MECHANISM FOR SEWING MACHINES Filed Feb. 4, 1941 3 Sheets-Sheet 1 Aug. 4, 1942. F, F; 2m I 2,292,258

FEEDING MECHANISM FOR SEWING MACHINES Fi led Feb. 4, 1941 3 Sheets-Sheet 2 Aug. 4, 1942. F z R 7 2,292,258

FEEDING MECHANISM FQR SEWING MCflINES Filed Feb. 4, 1941 3 Sheets-Sheet 5 derie 1% Z8587 Patented Aug. 4, 1942 OFFICE.

FEEDING MECHANISM FOR SEWING MACHINES Frederick F. Zeier, Fairfie'ld, Conn., assignor to The Singer Manufacturing Company,

Elizabeth, N. 1., a corporation of New Jersey Application February 4, 1941, Serial No. 377,295

12 Claims. (01. 112-215) This invention relates to feeding mechanisms for sewing machines.

One of the objects of this invention is to provide an improve-d form of feeding mechanism which is simple in construction and reliable in operation, and which may be actuated at high speeds with little vibration and overthrow.

Another object of the invention is the provision in a chain-stitch sewing machine of a feed ing mechanism which is compactly designed so that all its actuating connections can be disposed rearwardly of the zone of stitch-formation leavin the space forwardly of the usual looper or loopers devoid of mechanism, thereby giving access to the looper or loopers for the convenient threading or adjustment thereof.

With the above and other objects in view, as will hereinafter appear, the invention comprises the devices, combination and arrangements of parts hereinafter set forth and illustrated in the accompanying drawings of a preferred embodiment of the invention, from which the several features of the invention and the advantages attained thereby will be readily understood by those skilled in the art.

In the drawings:

Fig. 1 is a top plan View, partly in section, of a portion of the bed of a sewing machine having my improved feeding mechanism incorporated therein.

Fig. 2 represents a longitudinal vertical sectional view taken substantially along the line 2--2, Fig. 1, with the work-supporting plate,

throat-plate and presser-foot in elevation assembled in proper relationship upon the machinebed.

Fig. 3 represents a transverse vertical sectional view taken substantially along the line 3-3, Fig. 1.

Fig. 4 represents a transverse vertical sectional view taken substantially along the line 44, Fig. 1.

Fig. 5 represents a transverse vertical sectional view taken substantially along the line 55, Fig. 1.

The invention is illustrated as applied to the chain-stitch sewing machine forming the subject of my co-pen-ding application Serial No. 316,297, filed Jan. 30, 1940. That portion of the sewing machine shown comprises a bed I including front and rear vertical walls 2 and 3 connected together by two transverse partitions 4 and 5. Suitably attached upon the bed I is the usual work-supporting plate 6 fitted with a throat-plate I. J ournaled for rotation in a conventional roller-bearof the eccentric. As the ing 8 fixed in the transverse partition 5 is a mainshaft 9 carrying at its forward end a crank I0 connected through suitable mechanism to a looper-carrier ll mounted for oscillation upon a transverse fulcrum-shaft l2. Supported in the looper-carrier H is a thread-carrying looper l3 adapted to be oscillated in a plane parallel with the line of feed and coordinated with an endwise reciprocatory needle M to effect the production of chain-stitches.

The feeding mechanism for advancing the fabric past the stitch-forming devices comprises a feed-advance and -return rock-shaft l5 journaled at its opposite ends in bushing l6 and I1 fixed, respectively, in the transverse partitions 4 and 5 of the bed I. Clamped to the inner end of the feed-advance and -return rock-shaft is a depending rock-lever l8 connected at its lower end to one end of a forwardly extending pitman l9 embracing at its other end an adjustable eccentric 20 fixed on the main-shaft 9. To minimize friction between the pitman l9 and eccentric 20 a roller-bearing 2!, (see Fig. 5), is interposed between the pitman-strap and the surface main-shaft is rotated it will be understood that the feed-advance and -return rock-shaft l5 is rocked in its bearings and the extent of rocking movement is dependent upon the eccentricity of the adjustable eccentric 20. In the drawings the adjustable eccentric shown is constructed in accordance with the disclosure in the U. S. Patent to W. Myers, No. 2,128,031, issued Aug. 23, 1938, but it is to be understood that this is merely the preferred type of eccentric and that any other type may be used. To effect adjustment of the eccentric 20 the adjusting member 20' of the eccentric is provided with a notch 20", (see Fig. 1), which is adapted to be entered by a suitable detent, (not shown), whereby the adjusting member 20' is held stationary so that manual turning of the main-shaft 9 effects a change in the eccentricity of the eccentric. In this manner the stitch-length stroke of the feeding mechanism may be varied.

Mounted fast upon the feed-advance and -return rock-shaft I5 intermediate the bearing bushings It and I! are the upstandin spaced limbs of a U-shaped feed-rocker 22 which, through the medium of the set-screws 23 passing through the spaced limbs thereof, is adapted to move with the rock-shaft l5. Freely received in the upper ends of the spaced limbs of the feedrocker 22 is a pivot-bar 24 fixed by set-screws 25 in the bifurcated end of a feed-bar 26 formed with a vertically disposed channel 21 (Fig. 3),

adapted to receive the slotted shank 28 of a forwardly extending feed-dog 29 clamped in vertically adjusted position by a screw 30 threaded into the feed-bar 26. To assist in adjusting the feed-dog 29 to its proper elevation and maintaining the same in such adjusted elevation the shank 23 of the feed-do is provided with an adjusting screw 3! adapted to engage the feed-bar 26.

It will be seen from Fig. 3 that the feed-dog 29 extends for a considerable distance forwardly of the feed-bar 26 and in order to substantially nullify any vibrations which may be set up by the high speed actuations of this overhanging mass, the feed-rocker 22 is formed with a suitable counterweight 32. suflicient weight so that the feed mechanism is dynamically balanced to the extent that vibration is reduced to a minimum. In addition the counterweight 32 effectively reduces the inertia to be overcome in oscillating the feed-rocker 22. To this end the centers of the apertures formed in the feed-rocker 22 through which the feedadvance and return rock-shaft [5 projects coincide with a line passing through the center of mass, or gravity, of the feed-rocker. When so supported the effort required to oscillate the feed-rocker is proportional to its weight only.

The feedbar 26 has integrally formed therewith a forwardly and downwardly extending arm 33 which is connected preferably at its lower end to the upper end of a vertical link 34. The lower end ofthe link 34 is connected to a rock-lever 35 clamped upon a feed-lift rock-shaft 36 journaled at its opposite ends in bearing bushings 3'!- and 38 secured, respectively, inthe transverse partitions 4 and 5 of the bed I. The rockshaft 36=is restrained against endwise movement in its bearings by-two collars 39 and 40 which are secured upon the rock-shaft and engage the opposite ends ofvthe bearing bushing 31. At its inner end the feed-lift rock-shaft 36 has clamped thereon'a rock-lever 4| connected by a pitman 42 to a feed-lift eccentric 43 secured by set-screw 43* upon the reduced portion H! of the looperactuating crank l0 adjacent the partition 5. R0- tation of the mainshaft 9 oscillates the feedlift-rock-shaft 36-and the oscillations of the rockshaft impart to the feed-dog 2'9 rising-and-fallingmovements in proper timed relation with the advance-and return movements imparted to the feededog by the oscillations of the feed-advance and -return rock-shaft l5. It is preferable. that the link 34 be arranged substantially vertical for the reason that the vertical component of movement of the connecting pin between the link 34 and the lower end of the feed-bar-arm 33, as the link 34 pivots about its lower end, is at a minimum and therefore does not affect material.- lythe flatness of that portion of' the path of the feed-dog 29 which is above the throat-plate 1.

Itwill be observed in Figs. 1 and 3 that the arm 33 is formed at one side of the feed-bar 26 and that only one arm is used in the machine chosen to illustrate the present invention. It is to be understood however that the feed-bar may be formed with a second arm 33 disposed on the opposite side of the feed-bar which second arm would be desirable in the event the present invention was incorporated in a machine having an extremely wide feed-dog. The two arms would then prevent cramping of the feed-bar 26 on the pivot-bar 24.

It is to be understood also that it is desirable for the lower end of the arm 33 to be extended This counterweight. hasforwardly to a position as remote as possible from the pivotal support of the feed-bar 26 on the feed-rocker 24, for the reason that any play or looseness of fit existing in the connection between the link 34 and the arm 33 is held to a minimum at the feed-dog 29. Obviously if the arm 33 were shortened to the extent that the pivotal connection between the arm 33 and the link 34 was located adjacent the pivot-bar 24, any play between the arm 33 and the link 34 would be exaggerated at the feed-dog 29.

Referring to Figs. 1 and 2 it will be observed that the feed-advance and return rock-shaft E5, the feed-lift rock-shaft 36 and the main-shaft 3 are arranged in parallelism with each other; the relative location of the three shafts being such that the entire feed-actuating mechanism is positioned rearwardly of a longitudinal vertical plane passing through the stitching point. This is desirable in that it provides an open space substantially devoid of mechanism forwardly of the stitch-forming looper or loopers l3 into which the looper or loopers can be shifted in the usual manner for convenient threading, or through which convenient access may be had to the looper or loopers for the purpose of proper adjustment. It will be noted also that the rock-shafts l5 and 36 are preferably hollow and that each of these shafts is journaled at its opposite ends in substantial bearings supported in the transverse partitions 4' and 5; Also the feed-advance eccentric 20 and the feed-lift eccentric 43 are mounted on the main-shaft 9 at opposite sides of and closely adjacent to the transverse partitionon 5. From the above described features it will be appreciated that the present feeding mechanism is extremely rigid in construction and therefore positive in its action, and that the various parts have been made light inweight and balanced dynamically so that the feeding mechanism may be operated at high rates of speed of the order of 4500 to 5000 stitches a minute, with little vibration and without overthrow. The use ofthe various roller bearings reduces friction between the parts to a minimum.

It is obvious that the invention, as defined in the-appended claims, is not limited to the details of construction and arrangement of parts as shown; neither is it limited to the type of complemental stitch-forming mechanism disclosed, except where specifically so stated.

Having thus set forth the nature of the invention what I claim herein is:

1. A sewing machine having a bed including front and rear walls connected together by two transverse partitions, a main-shaft journaled in said bed, stitch-forming devices including a thread-carrying needle and a complemental looptaker disposed within the bed forwardly of said main-shaft, a feed-advance and -return rockshaft and a feed-lift rock-shaft each having its opposite ends journaled in said transverse partitions and in position so that an open space is provided forwardly of said loop-taker, a feed-bar, means operatively connecting said feed-bar to said feed-advance and -return rock-shaft and to said feed-lift rock-shaft, a feed-dog adapted to engage the work in the vicinity of the stitch-forming devices and having a shank projecting rearwardly for connection on said feed-bar, and means connecting said feed-advance and -return rock-shaft and said feedlift rock-shaft to said main-shaft for imparting work-feeding movements to said feed-dog. ,7

2. A sewing machine having a bed including front and rear walls connected together by at least one transverse partition, a main-shaft journaled in said bed, stitch-forming devices including a reciprocatory thread-carrying needle and a loop-taker complemental to said needle and disposed within the bed forwardly of said mainshaft, a feedadvance and -return rock-shaft and a feed-lift rock-shaft both journaled in said transverse partition rearwardly of the vertical plane containing the axis of the main-shaft, a feed-bar operatively connected to said feed-advance and -return rock-shaft and to said feedlift rockshaft, a feed-dog adapted to engage the work in the vicinity of the stitch-forming devices and having a shank projecting rearwardly for attachment on said feed-bar, and means connecting said feed-advance and -return rock-shaft and said feed-lift rock-shaft to said main-shaft for imparting work-feeding movements to said feeddog.

3. A sewing machine having a bed including front and rear walls connected together by at least one transverse partition, a main-shaft journaled in said bed, stitch-forming devices including a reciprocatory thread-carrying needle and a loop-taker complemental to said needle and disposed within the bed forwardly of said mainshaft, a feed-advance and -return rock-shaft and a feed-lift rock-shaft both journaled in said transverse partition rearwardly of the vertical plane containing the axis of the main-shaft, a feed-bar operatively connected to said feed-advance and -return rock-shaft and to said feed-lift rock-shaft, a feed-dog adapted to engage the work in the vicinity of the stitch-forming devices and having a shank projecting rearwardly for attachment on said feed-bar, a feed-advance eccentric and a feed-lift eccentric mounted on said main-shaft on opposite sides of and adjacent tosaid transverse partition, and means connecting said eccentrics with said feed-advance and -return rock-shaft and said feed-lift rock-shaft for imparting work-feeding movements to said feeddog.

4. A sewing machine having a bed including front and rear walls connected together by two transverse partitions, a main-shaft journaled in said bed, stitch-forming devices including a thread-carrying needle and a complemental looptaker disposed within the bed, a feed-advance and -return rock-shaft having its opposite ends journaled in said transverse partitions rearwardly of the main-shaft and adjacent the top of said bed, a feed-lift rock-shaft having its opposite ends journaled in said transverse partitions rearwardly of the loop-taker and adjacent the bottom of said bed, means connecting said feed-advance and -return rock-shaft and said feed-lift rock-shaft to said main-shaft for imparting oscillations to said rock-shafts, a feed-bar operatively connected to said feed-advance and -return rock-shaft and to said feed-lift rock-shaft, and a feed-dog adapted to engage the work in the vicinity of the stitch-forming devices and having a shank projecting rearwardly for attachment on said feed-bar to provide an open spaced forwardly of the looper-taker through which the latter may be readily accessible for adjustment or replacement.

5. A sewing machine having a bed provided with a pair of transverse partitions, a main-shaft journaled in said bed, a feed-advance and -return shaft and a feed-lift shaft journaled in said partitions, a feed-rocker mounted on said feed-advance and -return shaft intermediate said partitions, at feed-bar pivotally mounted on said feedrocker and provided with a forwardly and downwardly extending arm, a feed-dog having a rearwardly extending shank fastened on said feedbar, a depending link connected to the lower end of said feed-bar-arm, a rock lever connected at one end to said depending link and at its other end to said feed-lift shaft, and means operatively connecting said feed-advance and -return shaft and said feed-lift shaft to said main-shaft for imparting work-feeding movements to said feeddog.

6. A sewing machine having a bed provided with a pair of adjacent transverse partitions, a main-shaft journaled in at least one of said partitions, a feed-advance and -return shaft and a feed-lift shaft journaled in said partitions rearwardly of the main-shaft, a feed-rocker mounted on said feed-advance and -return shaft intermediate said partitions, a feed-bar carried by said feed-rocker and provided with a forwardly and downwardly extending arm, a feed-dog disposed forwardly of said main-shaft and having a rearwardly extending shank adapted for attachment on said feed-bar, a depending link connected to the lower end of said feed-bar-arm, a rock-lever connected at one end to said depending link and at its other end to said feed-lift shaft, a feedadvance eccentric and a feed-lift eccentric mounted upon the main-shaft, and means for connecting said eccentrics, respectively, to said feed-advance and -return shaft and to said feedlift shaft for imparting work-feeding movements to said feed-dog.

'7. In a sewing machine having a bed, a mainshaft journaled in said bed, a feed-advance and -return shaft and a feed-lift shaft also journaled in said bed, a feed-rocker mounted on said feed-advance and -return shaft, a feed-bar pivoted on said feed-rocker and provided with a forwardly and downwardly extending arm, a feed-dog having a rearwardly extending shank fastened on said feed-bar, a substantially vertically disposed link connected to the lower end of said feed-bar-arm, means connecting said link to said feed-lift shaft, and means operatively connecting said feed-advance and -return shaft and said feed-lift shaft to said main-shaft for imparting work-feeding movements to said feeddog.

8. A feeding mechanism for a sewing machine having a bed provided with a pair of transverse partitions and a main-shaft journaled in at least one of said partitions, comprising, a feed-advance and -return shaft journaled at its opposite ends in said partitions, a feed-lift shaft also journaled at its opposite ends in said partitions, means operatively connecting said feed-advance and -return shaft and said feed-lift shaft to said main-shaft, a feed-rocker carried by said feedadvance and -return shaft intermediate said partitions, said feed-rocker being provided with a counterbalance, a feed-bar pivoted to said feed-rocker, a feed-dog, an arm extending forwardly and downwardly from said feed-rocker, a rock-lever carried by said feed-lift shaft, and a link connecting the lower end of said feedbar-arm to said rock-lever.

9. A feeding mechanism for a sewing machine having a bed provided with a pair of transverse partitions and a main-shaft journaled in at least one of said partitions, comprising, a feed-advance and -return shaft journaled at its opposite ends in said partitions, a feed-lift shaft also journaled at its opposite ends in said partitions,

means operatively connecting said feed-advance and -return shaft and said feed-lift shaft to said main-shaft, a feed-rocker of substantial U- shape carried by said feed-advance and -return shaft intermediate said partitions, said feedrocker being formed with a Weighted section to provide a counterbalance, a feed-bar fulcrumed upon said feed-rocker, a feed-dog secured to said feed-bar, and means connecting said feed-bar to said feed-lift shaft.

10. A feeding mechanism for a sewing machine having a frame provided with a mainshaft, comprising, a feed-advance and -return shaft journaled in said frame, a feed-lift shaft also journaled in said frame, means operatively connecting said feed-advance and -return shaft and said feed-lift shaft to said main-shaft, a feed-rocker securedupon said feed-advance and -return shaft, the axis of said last named shaft passing through said feed-rocker at substantially'i-ts center of mass, a feed-bar pivoted to said feed-rocker, a feed-dog secured to said feedbar, and means for operatively connecting said feed-bar to said feed-lift shaft.

11. A feeding mechanism for a sewing machine having a frame provided with a mainshaft, comprising, a feed-advance and -return shaft journaled in said frame, a feed-lift shaft journaled in-said framein substantial parallelism with said feed-advance and -return shaft, means operativelyconnecting said feed-advance and -return' shaft and said feed-lift shaft to said main-shaft, a U-shaped feed-rocker having spaced upstanding limbs secured intermediate their ends upon said feed-advance and -return shaft, said feed-rocker having a weighted section between its limbs to provide a counterbalance, a feed-bar pivoted to the ends of the upstanding limbs of said feed-rocker, a feed-dog secured to said feed-bar, and means for operatively connecting said feed-bar to said feed-lift shaft.

12. A feeding mechanism for a sewing machine having a frame provided with a main-shaft, comprising, a feed-advance and -return shaft journaled in said frame, a feed-lift shaft journaled in said frame in substantial parallelism with said feed-advance and -return shaft, means operatively connectingsaid feed-advance and -return shaft and said feed-lift shaft to said main-shaft, a feed-rocker secured upon said feed-advance and -return shaft and having a weighted section at one side of said feed-advance and -return shaft, a feed-bar pivoted to said feed-rocker on the other side of said feed-advance and -return shaft opposite to said weighted section, a feed-dog secured to said feed-bar, and means including a substantially vertically disposed link for operatively connecting said feedbar to said feed-lift shaft.

FREDERICK F. ZEIER. 

